The overarching objective of the proposed research is to pilot test a newly developed observational coding instrument for study sequences of therapist-family interaction in sessions of Functional Family Therapy for adolescent drug abuse. The name of the instrument is the Functional Family Therapy Coding and Rating Scale (FFT CARS). The FFT CARS has undergone an initial round of pilot testing in which overall rates or proportions of specific types of therapist behavior have been studies and linked with adolescent and family outcomes. The current project would build upon and extend this pilot study of the FFT CARS by incorporating observational codes pertaining to the behavior of the family members during the sessions of FFT so to allow for the examination of theoretically relevant sequences of therapist-family interaction that may predict clinical outcomes. The specific aims of the propose project are: 1. To use an established family-based observational coding system to code the behavior of family members in sessions of FFT in which the behavior of the therapists have already been coded using the FFT CARS;2. Merge coded data on family behavior in sessions of FFT with existing coded data on therapist behavior in the same FFT sessions obtained in a prior pilot study of the FFT CARS. 3. Analyze the merged data to empirically identify sequences of therapist family interaction during sessions of FFT. 4. Model statistical linkages between certain type's in-session sequences in FFT and adolescent and family clinical outcomes. PUBLIC HEALTH RELEVANCE: The proposed research is designed to contribute to the development and refinement of Functional Family Therapy (FFT), a treatment of proven efficacy for adolescent substance abuse. Such clinical process-outcome studies may help to facilitate and propel the dissemination of FFT in community-based adolescent treatment settings. These advances could increase the likelihood that FFT will have a favorable impact at a public health level on drug-abuse problems of adolescents and their families.